The requirement to step down DC voltages frequently arises in electronics. Two conventional ways to achieve this include using a resistor divider or using a switched capacitor divider. A temperature coefficient and poor supply rejection of resistor dividers introduce errors in the output. In addition, a resistor divider cannot be used for voltage division in a sampled system. That is, high precision sampled systems (e.g. high-resolution data converters) require switched capacitor dividers to step down DC voltages.
However, conventional switched capacitor dividers suffer from significant leakage when both charging or discharging a sampling capacitor. Dominant leakage mechanisms include reverse biased leakage through the source-to-bulk (S/B) or the drain-to-bulk (D/B) diodes (which results in leakage onto the sampling capacitor) and channel leakage through the discharge switch (which results in leakage off the sampling capacitor). As the net leakage constitutes a nondeterministic error source, it cannot be calibrated out, thus making the reduction of the capacitor leakage significant in implementing high precision sampled systems.
Accordingly, there is a need for a voltage divider and a method of implementing a voltage divider overcoming the deficiencies of conventional voltage dividers.